Apparatus for stopping engines



A. KUEHN lll APPARATUS FOR STOPPING ENGINES March 22, 1966 2 Sheets-Shea?I 2 Filed Aug. 1 1963 .WUHNM bmj D www? IIJIIIIIII. IIIIIIIIIII vbeen set.

United States Patent Gliice 3,241,539 Patented Mar. 22,1966

3,241,539 APPARATUS FDR STOPPING ENGINES Andrew Kuehn III, St. Paul, Minn., assignor to Systematics, Inc., St. Paul, Minn., a corporation of Minnesota Filed Aug. 1, 1963, Ser. No. 299,261 6 Claims. (Cl. 12S-193) This invention has relation to apparatus for interrupting a line supplying power to an electrical circuit. The invention is disclosed in relation to apparatus for stopping engines and more particularly to apparatus for terminating the operation of an engine a predetermined period of time after the engine has stopped working and has been idling. A particularvapplication of this invention involves .use of the apparatus to interrupt the ignition current on an ignition fired automotive engine a predetermined period of time after the gear shift of the automobile has been placed in neutral or after the hand brake lever has Another adaptation of the invention will be useful to shut off the fuel supply on a truck-mounted diesel engine a predetermined period of time after its brake lever has been set or its gear shift put in neutral.

Apparatus made according to the present invention will nd utility in reducing the idling period of delivery vehicles. Excessive idling of an ignition red engine, for example, tends to cause loading up (excessive carbon deposits) due to the richness of the idle setting of the carburetor. Further, with power accessories such as the heater turned on in cold weather, for example, it is possible to discharge the battery on generator equipped vehicles due to lack of charging current during idling. Reduction of idling time will also reduce gas consumption and will reduce ignition point'wear.

In the case of diesel engines, it is often desirable to allow a short period of idling just before shut-olf where the engine has just terminated being under load. This is to allow the internal temperature to stabilize before shut-down. Use of the present invention will allow the driver to park the vehicle and leave the diesel engine running at idle when he leaves the truck after hauling a heavy load. 'Ihe apparatus of the invention will shut down the engine after a predetermined idling period has elapsed.

In order to cut off all power accessories except possibly the parking lights, the current from the battery and generator to the ignition switch is interrupted. Inasmuch as the shut-down of the engineinvolved may last overnight or even longer, it is very important that the current drain on the battery of the engine be zero or as low as possible. In order to achieve this result, the power for a timer and the other elements of the apparatus of the invention is obtained from the output side of the ignition switch. Thus when the power to the ignition switch is interrupted by this apparatus, there can be no further power dissipation through the timer unit. In the invention as disclosed herein, the only power drain on the battery during the shut-down period is that occasioned by a holding coil which stays across the battery to keep the normally closed contacts between the battery and the ignition switch in an open position.

Since the operation of the timer through its predetermined cycle automatically results in cutting the power to the timer, a transfer circuit has been provided which will insure that upon signal from the timer, the power to the ignition switch will be interrupted and a holding circuit, including a power relay coil as shown, will lock in to continue to interrupt this .power until such time as the apparatus of the invention is disabled by the vehicle operator when he again wants to use the engine.

An object of the invention is to provide an apparatus capable of operation in the aforesaid manner and which will include a timer. unit which will have the property of going through its complete cycling time beginning whenever it is re-energized, the cycling time being the same whether or not the preceding cycle was interrupted before its completion.

This cycling time will be predetermined by the components of the apparatus of the invention. In a usual case the period will be suiciently long so that the operator can unhurriedly start the engine and get comfortably set to drive the vehicle before releasing the hand brake lever to disable the apparatus. When the engine is started in cold weather, a considerably longer warm up or idling period may be needed before the operator is ready to release the hand brake lever or otherwise disable the apparatus. To allow unlimited idle time before the engine block is warm, a block 'thermostatic switch is connected across the power relay coil. When the block is cold, the thermostatic switch is closed thus preventing operation of the power relay and thereby preventing interruption of the power to the ignition circuit of the engine until after the engine is warmed up. As the engine block warms up into the operating range, the thermostatic switch opens, and the ypower to the ignition will be interrupted at the end of the next time cycle.

In the drawings:

FIG. 1 is a ver-tical sectional view of a portion of an automotive vehicle showing the physical relationship of an ignition switch, a hand brake lever and a mounting box containing certain components of the apparatus of the invention to the vehicle;

FIG. 2 is an enlarged vertical sectional view taken on the line 2 2 in FIG. 1;

FIG. 3 is a block diagram of the apparatus of the invention; and

FIG. 4 is a schematic diagram of one form of the electrical circuit of the invention.

Referring now to the drawings and numerals of reference thereon, an automotive vehicle 10 includes a hand brake lever 11 to which is attached a control wire 12 which runs through a cable 13 and is operably connected through a linkage 14 to an interlock switch 15 located inside of an apparatus component mounting box 16. Box 16 is affixed to a fire wall 17 of the automotive vehicle 10, as shown. An ignition switch 20 is mounted in a dash board 21 of the automotive vehicle, and the automotive vehicle is equipped with a source of electromotive force such as battery 22. In the usual case a generator will also be present, but has been omitted here to simplify the disclosure. The interlock switch 15 is maintained in a normally open position by its own internal biasing spring (not shown), and by a biasing spring 23. Operation of brake lever 11 to the set position will cause control wire 12 to move upwardly as seen in FIG. 2, thus causing a roller on the left end linkage 14 to move downwardly to close interlock switch 15.

Referring now to FIGS. 3 and 4, the battery 22 is connected to the vehicle body 10 by means of a ground strap 24. In automotive vehicles not incorporating the present invention, a hot main power line 25 from the battery runs to an ignition switch such as 20, but, in the apparatus illustrated herein, this line is broken and stopped short of the ignition switch. Instead a line 26 runs to that switch. A line 27 runs from the ignition switch 20 to the ignition system 28 and a similar line from the ignition switch to any land all accessories which are to be cut off with the cut-off of the ignition switch.

Lines 2S and 26 connect to a power relay unit 31 as shown in the block diagram. This unit is also shown in dotted lines in FIG. 4, and includes power relay coil 32 and power relay contacts 33, 34 and 35, as shown.

The hot line 25 also extends to a transfer relay unit 36 as shown in FIG. 3 which is also shown in dotted lines in FIG. 4 to include energy storage capacitor 37, trans- 3 fer relay coil 38 and normally open transfer relay contacts 39 and 40.

The line 27 from the ignition switch 20 is connected to a timer unit 44 which is indicated in full lines in FIG. 3 and in dotted lines in FIG. 4. As shown, this timer unit includes rst and second transistors 46 and 47, respectively, and R-C timing circuit including a capacitor 51 and a resistor 52, a thermistor type resistor 48, and resistors 53, 54 and 55.

Other timers having the characteristic of running through a complete timing cycle beginning whenever they are re-energized are suitable for use as the timer unit of thepresent invention although the timer unit herein disclosed and subsequently claimed has certain advantages not obtainable with the use of other timers.

A block thermostat and thermostatic switch 60 is situated in the engine block and is electrically connected across the leads from the transfer relay unit 36 to the power relay unit 31 in such a manner as to be capable of shorting out power unit relay coil 32. This thermostatic switch is normally open when the temperature of the block of the automotive vehicle is in its working range and is closed when the temperature of the block of the vehicle is below this working range or is cool or cold.

As seen in FIG. 4, a ballast resistor 61 is provided to vallow the block thermostatic switch to effectively disable the power relay coil 32; and a ballast resistor 62 is provided to limit the current through the block thermostat. A diode 63 is provided to prevent flow of current through the timer in the wrong direction if the polarity of the battery is accidently reversed.

As can best be seen from FIG. 4, when the ignition key is used to close the ignition switch 20 in the usual manner, power will be supplied to the ignition system from the battery 22, line 25, through normally closed contacts 34 and 33 of the power relay unit 31, line 26, the ignition switch 20, and line 27 to the ignition system 28. This electrical energy to the line 27 is transmitted to the diode 63 and through that diode to timer unit 44. When the hand brake lever 11 has been released, the parts will be positioned as shown in FIGS. 2, 3 and 4, and interlock switch will be open as in FIGS. 2 and 4. This separates the timer unit 44 and transfer circuit unit 36 from ground and no electrical energy will How in these components while interlock switch 15 is open. When the engine is already warm, the block thermostatic switch 60 will be open and will have no function in the circuitry at that time.

When, as contemplated by the apparatus of the invention, the operator of an automotive vehicle stops the vehicle and sets the hand brake by pulling back on the hand brake lever 11, the interlock switch 15 will be closed and a common line 64 connecting the timer unit, transfer relay unit, power relay unit and block thermostat will be grounded to the frame of the car and consequently to the battery 22.

This will start the timer unit 44 into its cycle, and a voltage will begin to build up across the capacitor 51 as current ows from the line 27 through diode 63 and resistor 52 until the base of transistor 46 is at a higher potential than the emitter. Both transistor 46 and transistor 47 will then conduct until the capacitor 51 is fully discharged. Resistor 52 will have a high enough resistance so that transistors 47 and 46 will turn olf. The time cycle will then be repeated.

The function of the thermistior type resistor 48 is to keep transistor 47 from conducting due to leakage current when it is warm. By using the thermistor to control the voltage at the base of the transistor 47, this voltage is held lower when hot than would be possible by a fixed resistor.

When both transistors 46 and 47 fire, a substantial volt age will be impressed across the energy storage capacitor 37 and transfer relay coil 38. When coil 38 is energized, the normally open contacts of the transfer relay contacts key, and leave the vehicle for an extended period.

39 and 40 will be closed and thus connect the main power line 25 from the battery to a power relay input line 65. The function of the capacitor 37 is to make available suicient energy so the transfer relay will hold on long enough to insure that the power relay will be energized sufficiently to lock itself in.

Energization of power relay coil 32 causes the normally closed power relay contacts 33 and 34 to open and normally open contacts 34 and 35 to close thus connecting main power line 25 to a power relay input line 66, effectively locking the power coil 32 into the circuit until such time as the interlock switch 15 is opened and the power relay relaxes.

The aforesaid electrical separation of power relay contacts 33 and 34 has disconnected the ignition switch 20 from the battery, and the ignition system of the automotive vehicle will be turned off. The timer unit is also turned olf since it was receiving its power from the line 27 through the ignition switch. The timer unit 44 and transfer relay unit 36 are likewise effectively removed from the circuit, and will remain disconnected during the time the power relay is energized.

Assume now cold weather conditions and that the engine is left off until it completely cools down. More time is needed to let the engine run at idling speed to warm up than is available during the cycling period normally provided by the timer unit. As pointed out above, when the block thermostat cools below a predetermined desired operating temperature, block thermostatic switch becomes closed, connecting ballast resistor 62 across the power relay coil 32. Then, when the ignition switch is closed and the vehicle is started in the usual manner, the timer will begin to cycle. At the end of the predetermined time period, voltage is applied across the power relay coil 32 and ballast resistor 62. The ohmic values of resistors 61 and 62 are such that the voltage drop across coil 32 and resistor 62 is insufficient to operate the power relay and the ignition system will not be interrupted. The timer, still being energized, will continue to recycle as long as the thermostatic switch is closed and the ignition system is energized. When the engine warms up sufficiently, the block thermostatic switch 60 will open. The power relay coil will be activated at the end of the next time cycle unless the operator has released the hand brake lever and opened the interlock switch'15.

In many instances, after the vehicle operator has left the engine idling and it has been shut down by the apparatus of the invention, the operator will return to the vehicle, turn oif the ignition switch, remove the ignition In this situation, the power relay coil 32 would remain energized except for the presence of the block thermostatic switch 60. As the vehicle engine cools down, a temperature will be reached at which the thermostatic switch 60 will close. This will reduce the voltage across the ballast resistor 62 and relay coil 32 to a point where it will be insuflicient to hold power relay unit 31 closed.

The power relay unit 3'1 will relax and thus disable the system completely. This will remove even the small drain of the coil 32 from across the battery.

While the invention has been disclosed as having the timer unit 44, the transfer relay unit 36, and the power relay unit 31 grounded to the battery and the frame of a vehicle through the instrumentality of an interlock switch operated by the hand brake llever 11, it is to be understood that this switch 15 could also be operated by the gear shift lever, for example. In this situation, a switch such as 15 will be closed when the gear shift is in neutral and will be open when the gear shift is in any other position. Other means of causing interlock switch 15 to be closed when the vehicle is no longer calling for power could be utilized within the spirit of this invention and the scope of the claims which follow. For example, a switch can be associated, With. lh@ trailer brake system on a tractor-trailer vehicle. Then either setting the trailer brakes, or the hand brake lever, or putting the gear shift lever into neutral would institute operation of the timer unit.

Throughout this specification, reference has been made to an ignition system and an ignition switch. It is to be understood that the lapparatus of the present invention is particularly well adapted to use with diesel engines and that on such engines where fuel cut-off happens automatically upon deactivation of the ignition switch, no change is necessary in the system.

On diesel engines, where handle shut-off (closing olf of fuel to the cylinders) is necessary to stop the engine, a fuel shut-off means which is connected to the output of the ignition switch in such a manner that interruption of power to the ignition switch results lin temporary shut-off of fuel to the diesel engine. Such a temporary shut-olf switch could also be operated directly by the timer unit 44, the transfer relay unit 36, or by the power relay unit 3=1 to shut off iiow of fuel to the engine at the end of the timing cycle. Such `aternporary interrupt switch or valve on the diesel fuel line will have the ability to close the fuel line at the end of the time cycle, to keep it closed at least a sufficient time to shut olf the engine, and t-hen to -automatically open. The particular mechanism of such a valve or switch forms no part of the present invention.

What is claimed is: K

1. In an apparatus for interrupting a power circuit a predetermined time period after and during the happening of a predesignated event, the combination with a power source, a location for use of power from said power source, and a power circuit between said source rand said location, of:

a timer unit;

a power relay unit;

a normally inoperative interlock device adapted to be operative during the happening of a predesignated event;

said power circuit including normally closed contacts interposed in said circuit between said source and said location for use, and constituting part of said power Irelay unit, said contacts being adapted to be separated from each other upon energization of said power relay unit;

a connection to said timer unit from .a point in said power circuit between said normally closed contacts and said location for use;

first means including said interlock device for completing a timer energizing circuit from said source, through said connection, said timer unit and back to said source;

said timer unit being operative a predetermined time after being energized to cause initial energization of said power relay unit;

second means operative upon initial energization of said power relay unit to continuously energize said unit; and

third means operative following the happening of said event to disable said second means.

2. In an apparatus for interrupting a power circuit a predetermined time period after and during the happening of a predesignated event, the combination with a power source, a location for use of power from said power source, and a power circuit between said source and said location, of:

a timer unit;y

a transfer unit;

a power relay unit;

a normally inoperative interlock device adapted to be loperative during the happening of a predesignated event;

said power circuit including normally closed contacts interposed in said circuit -between said source and said location for use, and constituting part of said 6 power relay unit, said contacts being adapted to be separated from each other upon energization of said power relay unit;

a connection to said timer unit from a point in said power circuit between said normally closed contacts and said location for use;

rst means including said interlock device for completing a time energizing circuit from said source, through said connection, said timer unit and back to said source;

said timer unit being operative a predetermined time after being energized to activate said transfer unit;

said transfer unit being operative when activated to initially energize said power relay unit;

second means operative upon initial energization of said power relay unit to continuously energize said unit; and

third means operative following the happening of said event to disable said first means.

3. In an apparatus for interrupting a power circuit a predetermined time period after and during the happening of a predesignated event and restoring said power circuit following the happening of said predesignated event, the combination with a power source, a location for use of power from said power source, a power circuit between said source land said location, and a first switch between said source and said location, said first switch constituting part of said power circuit, of:

a timer unit;

a first connection to said timer unit from a point on said power circuit between said first switch and said location for use;

a transfer unit;

a power relay unit;

a normally inoperative interlock switch adapted to be operative during the happening of a predesignated event and to become inoperative following the happening of said event;

a second connection lbetween said timer unit and said transfer unit;

a third connection to said transfer unit from said power source;

a fourth connection between said transfer unit and a first terminal of a control section of said power relay unit;

said power circuit including normally closed contacts interposed in said power circuit between said first switch and said power source, said contacts forming part of said power relay unit and said contacts being adapted to be separated from each other upon energization of said control section of said power relay unit;

a pair of normally open contactors in said power relay unit connected to said source and to said first terminal of said control section of said power unit respectively, said contactors being adapted to come in contact with each other upon energization of said power relay unit, thus to lock in a connection from said source to said first terminal;

a fifth connection between said timer unit, said transfer unit, -a second terminal of said control section of said power relay unit and la first terminal of said interlock switch;

a sixth control connection between a second terminal of said interlock switch and said source;

said timer being operative to energize said transfer unit a predetermined time period after the timer is energized =by the closing of the interlock switch;

said transfer unit being operative when energized to effectively connect said third and fourth connections to each other thus to energize the control section of said power relay unit.

4. The combination as specified in -claim 3 and la nor mally inoperative second switch adapted to be operative during the existence of a predesignated condition to disable the control section of said power rel-ay unit.

5. In an apparatus for interrupting a power line from a source of electromotive force to the ignition system of an engine of an automotive vehicle a predetermined time period after a vehicle carrying said engine has been stopped, the combination with an automotive vehicle having an engine, a source of electromotive force, an ignition system for said engine, a power circuit between said source and said system and including a main power line between said source and said system and an ignition switch interposed in said main power line between said ignition system and said source, of i a timer unit;

a transfer relay unit;

a power relay unit;

a normally open interlock switch adapted to be closed by action of a vehicle operatorpwhen said vehicle is stopped, and adapted to be opened by action of said vehicle operator in the process of putting the vehicle into motion;

a first control connection to said timer unit from a point on said main power line between said ignition switch and said ignition system;

a second control connection between said timer unit and said transfer unit;

Ia third control connection between said timer unit, said transfer relay unit, said power relay unit and a first terminal of said interlock switch;

a fourth control connection betweenl a second terminal of said interlock switch and said source of electromotive force;

a fth control connection between said power source and said transfer unit;

a sixth control connection between said transfer unit` vand a first terminal of a control section of said power relay unit;

a pair -of normally closed contacts interposed in said main power line between said source and said ignition switch, said contacts constituting part of said v power relay unit and said contacts being-adapted to -be separated from each other upon energization of said power relay unit;

a pair of normally open contactors in s aid power relay unit connected to said source and to said rst terminal of said control section of said power relay unit, re spectively, said normally open contactors being adapted to come into contact with each other upon energization of said power relay unit, thus to lock in a connection from said source to said-first terminal;

said timer being operative to energize said transfer unit a predetermined `ti-me period after the timer is energized by the closing of said interlock switch; and

said transfer unit zbeing `operative -when energized to effectively connect said fourth and fth contr-ol connections to eachl otherthus lto energize the control section of said power relay unit.

6. The combination as specified in claim'S;

a thermostatically operated switch in thermally conductive relationship to said engine, said switch adapted to be open when said engine is at a satisfactory operating temperature and closed whensaid engine is below said temperature; and

means including said switch for disabling said control section of said power relay unit when said thermostatically operated switch is closed.

No references cited.

MARK NEWMAN, Primary Examiner. 

5. IN AN APPARATUS FOR INTERRUPTING A POWER LINE FROM A SOURCE OF ELECTROMOTIVE FORCE TO THE IGNITION SYSTEM OF AN ENGINE OF AN AUTOMOTIVE VEHICLE A PREDETERMINED TIME PERIOD AFTER A VEHICLE CARRYING SAID ENGINE HAS BEEN STOPPED, THE COMBINATION WITH AN AUTOMOTIVE VEHICLE HAVING AN ENGINE, A SOURCE OF ELECTROMOTIVE FORCE, AN IGNITION SYSTEM FOR SAID ENGINE, A POWER CIRCUIT BETWEEN SAID SOURCE AND SAID SYSTEM AND INCLUDING A MAIN POWER LINE BETWEEN SAID SOURCE AND SAID SYSTEM AND AN IGNITION SWITCH INTERPOSED IN SAID MAIN POWER LINE BETWEEN SAID IGNITION SYSTEM AND SAID SOURCE, OF: A TIMER UNIT; A TRANSFER RELAY UNIT; A POWER RELAY UNIT; A NORMALLY OPEN INTERLOCK SWITCH ADAPTED TO BE CLOSED BY ACTION OF A VEHICLE OPERATOR WHEN SAID VEHICLE IS STOPPED, AND ADAPTED TO BE OPENED BY ACTION OF SAID VEHICLE OPERATOR IN THE PROCESS OF PUTTING THE VEHICLE INTO MOTION; A FIRST CONTROL CONNECTION TO SAID TIMER UNIT FROM A POINT ON SAID MAIN POWER LINE BETWEEN SAID IGNITION SWITCH AND SAID IGNITION SYSTEM; A SECOND CONTROL CONNECTION BETWEEN SAID TIMER UNIT AND SAID TRANSFER UNIT; A THIRD CONTROL CONNECTION BETWEEN SAID TIMER UNIT, SAID TRANSFER RELAY UNIT, SAID POWER RELAY UNIT AND A FIRST TERMINAL OF SAID INTERLOCK SWITCH; A FOURTH CONTROL CONNECTION BETWEEN A SECOND TERMINAL OF SAID INTERLOCK SWITCH AND SAID SOURCE OF ELECTROMOTIVE FORCE; A FIFTH CONTROL CONNECTION BETWEEN SAID POWER SOURCE AND SAID TRANSFER UNIT; A SIXTH CONTROL CONNECTION BETWEEN SAID TRANSFER UNIT AND A FIRST TERMINAL OF A CONTROL SECTION OF SAID POWER RELAY UNIT; A PAIR OF NORMALLY CLOSED CONTACTS INTERPOSED IN SAID MAIN POWER LINE BETWEEN SAID SOURCE AND SAID IGNITION SWITCH, SAID CONTACTS CONSTITUTING PART OF SAID POWER RELAY UNIT AND SAID CONTACTS BEING ADAPTED TO BE SEPARATED FROM EACH OTHER UPON ENERGIZATION OF SAID POWER RELAY UNIT; A PAIR OF NORMALLY OPEN CONTACTORS IN SAID POWER RELAY UNIT CONNECTED TO SAID SOURCE AND TO SAID FIRST TERMINAL OF SAID CONTROL SECTION OF SAID POWER RELAY UNIT, RESPECTIVELY, SAID NORMALLY OPEN CONTACTORS BEING ADAPTED TO COME INTO CONTACT WITH EACH OTHER UPON ENERGIZATION OF SAID POWER RELAY UNIT, THUS TO LOCK IN A CONNECTION FROM SAID SOURCE TO SAID FIRST TERMINAL; SAID TIMER BEING OPERATIVE TO ENERGIZE SAID TRANSFER UNIT A PREDETERMINED TIME PERIOD AFTER THE TIMER IS ENERGIZED BY THE CLOSING OF SAID INTERLOCK SWITCH; AND SAID TRANSFER UNIT BEING OPERATIVE WHEN ENERGIZED TO EFFECTIVELY CONNECT SAID FOURTH AND FIFTH CONTROL CONNECTIONS TO EACH OTHER THUS TO ENERGIZE THE CONTROL SECTION OF SAID POWER RELAY UNIT. 